The immune system has evolved multiple mechanisms to preserve immune homeostasis and protective immunity while sparing “self’ from autoimmune destruction. The initiation of immunity is a tightly controlled process that relies in part on interplay between inhibitory and activating receptors. Immunoglobulin-like transcripts (ILTs), which encompass both types of receptors, are encoded by rapidly evolving genes found in human and non-human primates. Immunoglobulin-like transcript 5 (“ILT5”) is a cell surface molecule that is a member of the immunoglobulin superfamily and is highly expressed on antigen-presenting cells (APCs), such as immature dendritic cells and monocytes.